The effect of orthodontic tooth movement on the human pulpal blood flow

本研究采用激光多普勒血流计（LDF）研究了施加侵入力对牙髓血流（PBF）的影响。测量参与者（年龄：24-31岁）重要的左上中门牙。短期(约。20秒)在被检查牙齿的切缘施加侵入力（app. 500 gf），在牙龈边缘约2 mm处测量PBF，并在被检查牙齿上应用不透明的黑色橡胶坝。在7名受试者中，有6名受试者在施加力过程中观察到LDF磁通信号的减少，但这种减少没有统计学意义。正畸托槽用4-META树脂粘接在检查牙的唇面和上第一磨牙上。一根不锈钢管在龈缘切口2毫米处粘接，以确保测量探针的精确导向。将改良的实用弓（0.016 * 0.022英寸）与托槽接合，并激活对检查牙齿施加持续的侵入力（约50 gf）。在施加侵入力之前、期间和之后反复测量PBF。此外，在检查的牙齿上施加短期（20秒）手动控制的侵入力（50 gf, 100 gf, 200 gf），并记录PBF。在施加力过程中，持续的侵入力显著降低了PBF。短时间内施加侵入力所产生的PBF减小不受持续施加侵入力的影响。结果表明，施加侵入力可使牙髓血流动力学降低，监测牙髓血流动力学可反映正畸治疗过程中牙髓血流动力学的变化。

The purpose of the present study was to examine the effect of intrusive force application on the pulp blood flow (PBF) using laser Doppler flowmeter (LDF). Measurements were made in vital upper left central incisors of the participants (age : 24-31). Short-term (approx. 20 seconds) intrusive force (app. 500 gf) was applied to the incisal edge of the examined teeth, and PBF measurements were made at approximately 2 mm to the gingival margin with opaque black rubber dam application to the examined teeth. In 6 out of 7 subjects, reduction of the LDF flux signal during the force application was observed, however, the reduction was not statistically significant. Orthodontic brackets were adhered to the labial surface of the examined tooth and upper first molars using 4-META resin. A stainless steel tube was cemented at 2 mm incisal to the gingival margin securing an exact guidance for the measurement probe. A modified utility arch (0.016 * 0.022 inch) was engaged to the brackets and activated to exert continuous intrusive force (approximately 50 gf) to the examined tooth. PBF was repeatedly measured before, during and after the intrusive force application. In addition, short-term (20 seconds) manually-controlled intrusive force (50 gf, 100 gf, 200 gf) was applied to the examined tooth and PBF was also recorded. Continuous intrusive force produced significant reduction of PBF during the force application. The reduction of PBF produced by the short term intrusive force application was not effected by the continuous intrusive force application. Results obtained suggest that the intrusive force application produces reduction of PBF and that monitoring of PBF indicates the change of the pulpal haemodynamics during Orthodontic treatment.